Back light illuminating unit

ABSTRACT

A frame disposed on the rear side of a liquid crystal unit ( 2 ) has in the front surface sheet thereof an opening almost the size of the liquid crystal unit ( 2 ), and is constituted so that a translucent optical diffusion sheet is tensely provided on the opening in a thin-box-form. An inverter printed board ( 14 ) provided with an inverter circuit ( 16 ) and a cold cathode ( 22 ) are integrally coupled to this frame directly or indirectly via a retainer to unitize the frame, the inverter circuit ( 16 ) and the cold cathode ( 22 ). The electrode lead wire of the cold cathode ( 22 ) is connected to the high-voltage output terminal of the inverter circuit ( 16 ). A connector ( 20 ) for connection to an external wiring is fixed to the inverter printed board ( 14 ) or the frame to supply electricity to the inverter circuit ( 16 ) via the connector ( 20 ) and apply high voltage to the electrode of the cold cathode ( 22 ) from the inverter circuit ( 16 ). Accordingly, a liquid crystal display-use back light illuminating device can be reduced in size and thickness to enhance safety and reliability at assembling.

FIELD OF THE INVENTION

The present invention relates to backlight illumination unit for use in liquid crystal devices such as personal computers or television sets or car-navigation system.

BACKGROUND OF ART

In recent years, with regard to liquid crystal display electronic devices such as personal computer or car-navigation system and the like, liquid crystal display devices with backlights are widely used. As a light source of this backlight, fluorescent lamp such as cold cathode fluorescent lamp and the like are used.

The liquid display devices of this kind comprises, as shown in FIG. 15, a liquid crystal unit (2), a lamp unit (6) provided with cold cathode fluorescent lamp (4), liquid crystal control unit (8), inverter unit (10) and connector (12) and these devices are electrically connected by means of electric cords as shown in the drawing, and are mounted on the personal computers or car-navigation system. The inverter unit (10) is supplied with power source by means of the connector (12), and the liquid crystal control unit (8) is built to input the power source and control signal through the connector (12). Furthermore, a product of integrally combined liquid crystal unit and liquid crystal control unit has been developed.

When the liquid crystal display device is designed to be of a small size and thin unit, if a lamp unit and inverter unit are separately built, such a unit is of an extremely inconvenient, and is not fit to a small size unit of liquid crystal display device. Moreover, when the lamp unit and the inverter unit are separately built, a high voltage supply electric wire for connection of the inverter unit and the lamp unit tends to become a long line, and a safety is spoiled which is one of the problems.

In case the high voltage electric wire becomes longer, electric current leaks due to floating capacity between earths which results in the drop of voltage before the voltage gets the lamp portion. I this case, a problem occurs as requirement of readjustment of the inverter unit become necessary.

An object of the present invention is to solve the foregoing problems.

DISCLOSURE OF THE INVENTION

The present invention comprises a frame, disposed behind the liquid crystal unit, cold cathode fluorescent lamp, inverter printed board incorporated with inverter, and those devices are integrally combined to form a simple unit. The frame is formed in a thin box type, and an aperture portion of a size almost identical with the liquid crystal unit is formed on a surface plate of the frame. A light diffusion plate of light permeation type is affixed to the aperture portion of the surface plate of the frame. The lead wire of the electrode of the cold cathode fluorescent lamp connected to the high voltage output terminal of the inverter circuit, and a connector for connection of an external wiring is fixed to the frame or the board, and power source is supplied to the inverter circuit through the connector, and the high voltage is supplied to the electrode of the cold cathode fluorescent lamp from the inverter circuit.

Furthermore, the present invention is so designed that the inverter printed board is fixed to the inside of the frame, and the periphery of the inverter printed board surrounds the inner wall surface of the frame.

Still furthermore, the present invention is so designed that the inverter printed board is fixed and disposed on an outer wall surface of the frame, and the lead wire of the cold cathode fluorescent lamp is led to through hole of the inverter printed board through holes bored on the frame, and the lead wire is connected to the high voltage output terminal of the inverter printed board.

The present invention is so designed that the inverter circuit and the cold cathode fluorescent lamp forms a unit by integrally coupling the cold cathode fluorescent lamp to the inverter printed board provided with the inverter circuit by means of a retainer member, and the lead wire of the electrode of the cold cathode fluorescent lamp is connected to high voltage output terminal of the inverter circuit, and a connector for connection with the external wiring is fixed to the inverter printed board, and the power source is supplied to the inverter circuit through the connector, and the high voltage is supplied to the electrode of the cold cathode fluorescent lamp from the inverter circuit.

This invention is so designed that a surface plate of a frame is formed with an aperture portion of size almost same with a liquid crystal unit and a light diffusion plate of light permeation type is affixed to the aperture portion and the frame formed in a thin box type is disposed behind the rear side of the liquid crystal unit is fixed with an inverter printed board provided with an inverter circuit, and a cold cathode fluorescent lamp is disposed inside of the frame, and the cold cathode fluorescent lamp is integrally coupled to the frame by means of a retainer to form a simple unit of the frame, inverter circuit and cold cathode fluorescent lamp, and an acryl plate is disposed inside of the frame in opposition to the cold cathode fluorescent lamp, and the surface of the acryl plate is opposed to the aperture portion of the frame, and the lead wire of the electrode of the cold cathode fluorescent lamp is connected to the high voltage output terminal of the inverter circuit, and a connector for connection with an external wiring is fixed to the frame or the board, and the power source is supplied to the inverter circuit through the connector, and the high voltage is supplied to the electrode of the cold cathode fluorescent lamp from the inverter circuit.

The present invention is so designed that a cold cathode fluorescent lamp is disposed in the inverter printed board provided with the inverter circuit so that the lamp projects to the side of the board, and a retainer plate is fixed to the inverter printed board so that the plate projects to the side of the board, and the cold cathode fluorescent lamp is retained to the retainer plate by means the retainer to form a simplified unit of the inverter circuit, cold cathode fluorescent lamp and the retainer plate, and the lead wire of the electrode of the cold cathode fluorescent lamp is connected to the high voltage output terminal of the inverter circuit, and a connector for connection to an external wiring is fixed to the inverter printed board, and the power source is supplied to the inverter circuit through the connector, and the high voltage is supplied to the electrode of the cold cathode fluorescent lamp from the inverter circuit.

The present invention is so designed that the inverter printed board provided with the inverter circuit is fixed to the frame disposed behind the liquid crystal unit wherein its surface plate is formed in thin box type and is formed with an aperture portion of a size almost identical with the crystal unit, and the light diffusion plate of light permeation type is affixed to the aperture portion, and the cold cathode fluorescent lamp is disposed inside of the frame, and a retainer plate is fixed to the inside of the frame so that it projects to the side of the inverter printed board, and the cold cathode fluorescent lamp is coupled to the retainer plate to form a simple unit of the frame, inverter printed board, cold cathode fluorescent lamp, and retainer plate, and the surface plate of the acrylic resin plate is disposed to oppose the aperture portion of the frame, and the lead wire of the electrode of the cold cathode fluorescent lamp is connected to the high voltage output terminal of the inverter circuit, and a connector for connection to the external wiring is fixed to the frame or the inverter printed board, and the electric power source is supplied to the inverter circuit through the connector, and the high voltage is supplied to the electrode of the cold cathode fluorescent lamp from the inverter circuit.

Furthermore, the present invention forms a mirror surface for reflection of the light of the cold cathode fluorescent lamp on the frame to be directed to the acrylic resin plate.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an A-A line cross section showing an embodiment of this invention;

FIG. 2 shows an explanatory elevation showing an embodiment of this invention;

FIG. 3 shows an showing an embodiment of this invention;

FIG. 3 shows an explanatory elevation showing an embodiment of this invention;

FIG. 4 shows a B-B line cross section;

FIG. 5 shows a plan view elevation showing another embodiment of this invention;

FIG. 6 shows a C-C line cross section;

FIG. 7 shows a D-D line cross section;

FIG. 8 shows an explanatory view of a lamp holding mechanism;

FIG. 9 shows a cross section showing a connecting mechanism of cold cathode fluorescent lamp and printed board;

FIG. 10 shows an explanatory elevation showing another embodiment of this invention;

FIG. 11 shows an explanatory elevation showing another embodiment of this invention;

FIG. 12 shows an explanatory elevation showing another embodiment of this invention;

FIG. 13 shows an E-E line cross section;

FIG. 14 shows an explanatory elevation showing another embodiment of this invention, and

FIG. 15 shows an explanatory view of the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The embodiments of the present invention will be described in details in the following by referring to the drawings.

In FIG. 2, numeral (14) shows a printed board comprised of glass epoxy resin and the like, and a high voltage generating circuit including ceramic piezoelectric transformer or winding transformer, namely, an inverter circuit (16) and dimmer circuit (18) connected to the circuit are formed by print wiring technology. A connector (20) is fixed to the side of the print board (14) and two terminals to which the power source is inputted and one terminal to which the dimmer signal is inputted are provided to the input side of the connector (20). The inverter circuit (16) and the dimmer circuit (18) are connected to the connector (20), and the power source is inputted from the outside through the connector (20). The power source and the dimmer signal are inputted to the dimmer circuit (18) through the connector (20). Numeral (22) shows a cold cathode fluorescent lamp (CCFL) that lights with high voltage which is bent in -shape, and its both ends are fixed to the printed board (14) by means of the retainer metal fitting (24). A lead wire (26) of one electrode of the cold cathode fluorescent lamp is soldered and fixed to a high voltage output terminal (28) of the inverter circuit (16) in the shortest distance, and the other lead wire (26) of the cold cathode fluorescent lamp is connected to an earth potential terminal (30) of the printed board (14) by means of soldering. By this arrangement, the wiring of the high voltage wire between the lead wire (26) of the cold cathode fluorescent lamp (22) and the inverter circuit (16) is no longer needed. Another output terminal (32) of the inverter circuit (16) is connected to the earth potential. An illumination unit for backlight is constructed by the printed board (14) and the cold cathode fluorescent lamp (22). The embodiment of the present invention provides the following structure to the foregoing construction. Numeral (34) shows a frame, and a surface plate has an aperture portion of a size almost same with the liquid crystal unit (2) (refer to FIG. 15), and is a thin box type whose side is open. Alight diffusion plate of light permeation type (44) is affixed to the aperture portion of the frame (34) to form a light uniform irradiation surface that irradiates the light uniformly. The frame (34) is disposed behind the liquid crystal unit (2), and is fixed to the unit. For this reason, the frame (34) is provided with a fixing member (illustration is omitted) for fixing the frame (34) to the liquid crystal unit (2) and a fixing member (not shown) for fixing the frame (34) to the body of the liquid crystal display electronic equipment. As shown in FIG. 4, the cold cathode fluorescent lamp (22) is housed and disposed in U-shape of the frame (34). A light diffusion plate (36) of light permeation type formed with numerous small delicate convex portions of pyramid type is fixed and disposed on the rear surface portion of the frame (34), and a back surface open portion of the frame (34) is shielded by the light reflecting diffusion plate (36). A transparent acrylic plate (38) is disposed on the open central portion of the frame (34), and three direction edge portions of the acrylic plate (38) are supported in U-shape of the frame (34). The acrylic plate (38) leads the light of the cold cathode fluorescent lamp (22) in a horizontal direction from the end surface side, and a uniform white light irradiated surface is formed on the elevation side of the acrylic plate (38). On the inner surface of the U-shape portion of the frame (34), a mirror surface (34 a) reflecting the light in the end surface direction of the acrylic plate (38) is formed. On the elevation side open portion of the frame (34), a transparent light diffusion plate (40) and light leading plate (42) are laminated and they are mutually cemented, and thus, a uniform white light irradiated surface is formed, and the open portion of the elevation side of the frame (34) is shielded by this light irradiated surface (44). Only each one side of the light diffusion plate (40) and the light leading plate (42) forming the light irradiated surface (44) are fixed to the one side of the U-shape portion of the frame thereby avoiding thermal contraction phenomenon thereof. One side portion (34 b) of the frame (34) is notched of its upper portion, and this notched end surface opposes to one side portion of the printed board (14), and the one side portion (34 b) is fixed to the one side portion of the print board (14) by means of screw (46). The periphery of the acrylic plate (38) is supported in a holding space of square type surrounded by the end face of the printed board (14) and the frame (34). In the foregoing construction, the cold cathode fluorescent lamp (22), light diffusion plate (40), light leading plate (42) and acrylic plate (38) are integrally coupled, and as a whole, a thin plate type unit of the backlight device is constructed. This backlight illumination unit is disposed in layers over the back surface of the liquid crystal unit to irradiate the liquid crystal plate. In the foregoing embodiment, the cold cathode fluorescent lamp (22) is fixed directly on the printed board (14) by means of the lamp retainer member (24), but the cold cathode fluorescent lamp (22) may be fixed to the frame (34) or as shown in FIGS. 5-9, a lamp retainer plate (50) is separately provided from the frame (34), and the cold cathode fluorescent lamp (22) is retained on the lamp retainer plate (50) by means of a fitting type lamp retainer member (52), and the lamp retainer plate (50) may be fixed to the printed board (14) by means of the screw (14) as another option. In FIG. 6, the cold cathode fluorescent lamp (22) along with the lamp retainer plate (50) are loosely fitted in the inside of the U-shape portion of the frame (34), and the frame (34) is retained and fixed to the printed board (14) formed with the inverter circuit (16) and the dimmer circuit (18) by means of the screw (54).

In this embodiment, except for the structure of holding the cold cathode fluorescent lamp (22) by the lamp retainer plate (50), it is identical with the first embodiment. Both ends of the cold cathode fluoresecent lamp (22), as shown in 7, are disposed on the printed board (14), and a lead wire (56) of the electrode of one end of the cold cathode fluoescent lamp (22) is, as shown in FIG. 9, connected to the high voltage output terminal (58) of the inverter circuit of the printed board (14) by means of the metal retainer (59) with soldering, and the lead wire of the other electrode is connected to the earth of the printed board (14) by means of soldering. The lead wire (56) may be soldered to the high voltage output terminal (58) of the printed board (14) directly without using the metal retainer (59). The lamp retainer member (52) is made of elastic material, and the cold cathode fluorescent lamp (22) is pressure fitted through a gap of upper portion by resisting the elasticity of the retainer member (52) so that a cold cathode fluorescent lamp (52 a) may be mounted in the retainer concaved portion (52 a).

Furthermore, another embodiment of the present invention will be described in the following by referring to FIG. 10.

Numerals (60), (62), (64) show direct pipe type cold cathode fluorescent lamps, and each end portion is fixed to one side of the printed board (14) formed with the inverter circuit (16) and the dimmer circuit (18), and each other end is fixed to a support plate (68) made of glass epoxy resin plate or the like by means of a retainer metal member (70). A lead wire (78) of electrode of each end of the cold cathode fluorescent lamps (6) (62) is connected with soldering to high voltage output terminals (72) (74) (76) of the inverter circuit (16). The output terminal (80) forming a pair with the high voltage output terminals (72) (74) (76) of the inverter circuit (16) is earthed to the printed board (14). A line (82) made of conductor material is formed on support plate (68), and this line (82) is connected to a lead wire (84) of electrode of each other end of the cold cathode fluorescent lamps (60) (62) (64) by means of the soldering. The line (82) earthed with the printed board (14) through a connector (86) fixed to the support plate (68) and a connector (88) fixed to the printed board (14) and a low voltage cord (90) connecting connectors (86) (88).

In the foregoing construction, the input power source is supplied to the inverter circuit (16) through the connector (20) fixed to the printed board (14), and the input power source and the dimmer signal are inputted to the dimmer circuit (18) by means of the connector (20) and lighting, brightness of the cold cathode fluorescent lamps (60) (62) (64) are controlled by the inverter circuit (16).

For reference, a frame disposed behind the rear side of liquid crystal unit (2) is provided wherein an aperture portion of a size almost the same size of the liquid crystal unit is provided on a surface plate and is formed in a thin box type and a light diffusion plate of light permeation type is affixed to the aperture portion, and in this frame, a printed board (14), support plate (68), cold cathode fluorescent lamp (60) (62) (64) are built in, and a unit may be formed by the frame, printed board, cold cathode fluorescent lamps.

FIG. 11 shows an embodiment wherein both terminals of a plurality of U-shape cold cathode fluorescent lamps (92) (94) are fixed to the printed board (14) on which the the inverter circuit (16) and the dimmer circuit (18) are formed by means of a retainer member (96).

The lead wire of the electrode of one end of the cold cathode fluorescent lamps (92) (94) is connected with soldering to high voltage output terminals (98), (100) of the inverter circuit (16), and an output terminal (80) forming a pair with the high voltage output terminal of the inverter circuit (16) is connected to the earth potential. The lead wire of the electrode of the other end of the cold cathode fluorescent lamps (92), (94) is connected with soldering to the earth potential of the printed board (16). The power source is inputted to the inverter circuit (16) by means of the connector (20), and the power source and the dimmer signal are inputted to the dimmer circuit (18) by means of the connector (20).

For reference, in this embodiment, similar to the foregoing, the frame is disposed behind the liquid crystal unit (2) wherein the surface plate is formed with an aperture portion of size almost same with the liquid crystal unit (2) and is formed in thin box and the light diffusion plate of light permeation type is affixed to the aperture portion, and the printed board (14), cold cathode fluorescent lamps (92), (94) are built in the frame, and the frame and the printed board and the cold cathode fluorescent lamps may be coupled to form a unit.

Another embodiment of this invention will be described in the following by referring to FIGS. 12 and 13.

Numeral (102) shows a frame made of metal, plastic and the like wherein a surface plate is formed with an aperture portion, and is formed in thin box. A fixing member (18) for fixing a screw (106) to a body (104) of liquid crystal display electronic unit such as television and the like and a fixing member (110) made of a stud for fixing with a screw (112) to the liquid crystal (2) are provided on the frame (102). A light leading plate (112) and a light diffusion plate (114) of light permeation type are pasted to the aperture portion of the frame (102). The aperture portion forms a light irradiation surface, and the light irradiation surface is set to a size almost equal to the liquid crystal unit (2). A light diffusion surface of light reflection type is formed on the bottom surface of the frame (102), and a light reflection plate (116) of triangular cross section is fixed to the bottom surface. Numeral (118) denotes a cold cathode fluorescent lamp, and is fixed to the bottom surface of the frame (102) by means of a holder base (120) and a retainer member (122). In adjacency of the electrode of the cold cathode fluorescent lamp (118), the inverter printed board (14) is fixed to the bottom surface of the frame (102) by means of the screw (124). A lead wire (126) of one electrode of the cold cathode fluorescent lamps (118), (119) is fixed to the high voltage output terminal of the inverter printed board (14) by means of soldering, and a lead (128) of the other electrode of the cold cathode fluorescent lamps (118), (119) is connected to the earth potential terminal of the inverter printed board (14) by means of soldering. A connector (130) is fixed to the frame (102), and the connector (130) is connected to the connector (20) of the inverter printed board (14).

In the foregoing construction, the frame (102), cold cathode fluorescent lamp (118), inverter printed board (14) are integrally coupled to form a thin box type unit as a whole, and the unit is mounted on the rear surface of the liquid crystal unit (2) to irradiate the liquid crystal plate of the liquid crystal unit (2).

For reference, in the above embodiment, the inverter printed board (14) is disposed inside of the frame (102) by shutting down the outside but, as shown in FIG. 14, the lead wires (126), (128) of the cold cathode fluorescent lamp (118) built in the frame (102) which is fixed to the outer wall surface of the bottom portion of the frame (102) are led to a through hole of the printed board (14) through a hole (132) bored on the frame (102), and the lead wire may be soldered to the printed board (14).

Possibility of Use for Industry

The present invention, as described in the foregoing, provides a unit of the cold cathode fluorescent lamps, inverter printed circuit board by coupling, and this unit leads to a possibility of materializing a smaller and thinner model of an entire unit of the backlight, and yet, the use of high voltage wire is not needed which provides the use of high voltage wire is not needed and provides a safety, and reliability of operation which are some of effects brought by the present invention. 

1-10. (Cancelled)
 11. A backlight illumination unit comprises a frame disposed behind a liquid crystal unit which is formed in a thin box type with an aperture portion of a size almost same as the liquid crystal unit on its surface plate and affixing a light permeation plate of light transmission type to the aperture portion, a cold cathode tube built in the frame, and printed board provided with an inverter circuit, wherein the inverter printed board is fixed to a lower surface of a bottom plate of the frame, and the frame, cold cathode tube and the inverter printed board are integrally coupled to form a simplified unit, and the frame is bored with holes, and a lead wire of electrode of the old cathode tube is connected to a high voltage output terminal of the inverter circuit through the holes, and a connector for connection with an external wiring is fixed to the inverter printed board, and power source is supplied to the inverter circuit through the connector, and high voltage is supplied to the electrode of the cold cathode tube from the inverter circuit. 